# Some aspects of the N=2 superstring.

Joaquim Gomis

^{1}Abstract: The string model with /ital N/=2 world-sheet supersymmetry is approachedvia ghosts, Becchi-Rouet-Stora-Tyutin cohomology, and bosonization. Someamplitudes involving massless scalars and vectors are computed at the treelevel. The constraints of locality on the spectrum are analyzed. An attempt ismade to ''decompactify'' the model into a four-dimensional theory.

Topics: N=2 superstring (66%), Bosonization (54%), String (physics) (54%), Supersymmetry (53%), Cohomology (53%)

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Abstract: We prove that critical and subcritical N = 2 string theory gives a realization of an N = 2 superfield extension of the topological conformal algebra. The essential observation is the vanishing of the background ghost charge.

13 citations

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Abstract: There are two different spectral flows of the N = 2 superconformal algebras (four in the case of the topological algebra). The usual spectral flow, first considered by Schwimmer and Seiberg, is an even transformation, whereas the spectral flow previously considered by the author and Rosado is an odd transformation. We show that the even spectral flow is generated by the odd spectral flow, and therefore only the latter is fundamental. We also analyze thoroughly the four “topological” spectral flows, writing two of them here for the first time. Whereas the even and the odd spectral flows have quasi-mirrored properties acting on the antiperiodic or the periodic algebras, the topological even and odd spectral flows have drastically different properties acting on the topological algebra. The other two topological spectral flows have mixed even and odd properties. We show that the even and the even-odd topological spectral flows are generated by the odd and the odd-even topological spectral flows, and therefore only the latter are fundamental.

11 citations

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Abstract: We study the N = 2 string with a real structure on the (2,2) spacetime, using BRST methods. Several new features emerge. In the diagonal basis, the operator exp ( λ ∫ z J tot ), which is associated with the moduli for the U(1) gauge field on the world-sheet, is local and it relates the physical operators in the NS and R sectors. However, the picture-changing operators are non-invertible in this case, and physical operators in different pictures cannot be identified. The three-point interactions of all physical operators lead to three different types of amplitudes, which can be effectively described by the interactions of a scalar NS operator and a bosonic spinorial R operator. In the off-diagonal bases for the fermionic currents, the picture-changing operators are invertible, and hence physical operators in different pictures can be identified. However, now there is no local operator exp ( λ ∫ z J tot) that relates the physical operators in different sectors. The physical spectrum is thus described by one scalar NS operator and one spinorial R operator. The NS and R operators give rise to different types of three-point amplitudes, and thus cannot be identified.

10 citations

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Abstract: A free-field formulation of N =2 topological supergravity is obtained with a suitable gauge fixing of two-dimensional topological Yang-Mills theory, taking as the gauge group a contraction of Osp(2|2). We also give a superfield description of the action and its symmetry currents.

3 citations

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